Aberdeen has never been formally recognised as an Assay office. The Aberdeen Hammer-men were fairly well organised, but their silver marking was more haphazard, despite attempts to regulate it in 1646. Marks of AB, ABD or ABDN appear sometimes with 1, 2 or 3 cross-like larks, or castles. Silver continued to be made, and marked, in Aberdeen, even after the 1836 Act gave Edinburgh and Glasgow the sole rights of Assay.